Take a moment and think about all of the sensitive data kept on your computer. Account passwords, addresses, phone numbers, access to bank accounts and other financial services, and maybe even your social security number. Almost every aspect of your identity is kept on this little machine. Now imagine you want a new one. So, you go out and buy a shiny new laptop. What do you do with the old one? Just toss it, right?
Wrong! If you just throw out your old computer, all of that personal information is still available to any tech-savvy thief. Merely deleting a file in the traditional fashion will not truly “delete” it. With a few techniques, a file sent to the recycle bin and emptied can be recovered if the deletion was recent enough.
So how can you erase a hard drive completely? Well, there a few techniques that anyone can employ to protect their identity.
Disclaimer: Please keep in mind that the following software and techniques will ERASE your hard drive and you will not be able to get your data back. That’s the whole point.
Formatting
Most people’s first instinct would be to just reformat their drive to get rid of data. But there are all sorts of formatting that can be done.

First, you can perform what is called a high level format. Sometimes, this is referred to as a quick format. This method is not secure seeing as it only erases the boot sector and partition table, thus leaving all of the other files intact and accessible through purpose built software.
There is also low level formatting, referred to officially as “disk reinitialization.” This process goes through your disk and sets values to zero and will erase a hard drive completely.
For more advanced users, you can also change the number of passes that the format goes through. The more passes, the more secure it will be because the format goes through the disk the specified number of times and writes over the information with junk.
As you would expect, more passes take more time, but more passes means your data is better scrambled and harder to recover.
This process sounds like it would do the trick, but there are some catches. If you use a different file system than the one used to originally format the disk, or if you have multiple partitions, not all of your data will be thoroughly erased.
Thus, formatting the disk is not the preferable way to really, securely erase your data. Instead, there are some freeware tools you can use to make sure your information is gone.
If you do want to go the reformat route, MakeUseOf already has some good articles on how to do that here and here. You may have to use your OS disk, or software that came with your drive to perform the format you want.
Darik’s Boot And Nuke
If you checked out Varun’s article linked above, you’ll notice he mentions Darik’s Boot and Nuke. Let’s take a closer look at that tool.
DBAN, as it is shortened, is a nice little application that lets you completely erase your data. You can download it for Intel/AMD machines and Apple Power Mac machines by clicking “Downloads“ at the top of the home page. You should see the following.

Download the ISO for your system and burn it to a disk. Next, pop the disk into your hard drive and boot from it. This may require you to press F12 at the BIOS screen (the first screen you see when your computer boots up) and choose to boot from your CD/DVD drive. After the CD boots up, you should see the following.

Hit Enter and the program should boot a few things up before settling on the next screen.

Hit Space when the arrow is pointing at the disk you want to wipe and hit F10 to start the process. The process will start and you should see something like this.

Let it run through the whole process and you should get a screen letting you know the process was successful.

DBAN is easy and performs well. There are other options to get rid of your data for good.
Get Physical
The absolute best way to make sure your data is completely gone is to just destroy the drive. Clearly, this is only an option if you are going to dispose of the drive afterwards.
There are a few ways to go about this. You could get some high powered magnets and wipe the drive a few times with them. This scrambles all the data that is written magnetically on the disk.
Another option is to wail on the drive a few times with a hammer. Please remember to wear proper safety accessories such as safety glasses when using tools.
Finally, you can always take the drive apart to make sure the disk gets completely demolished. To do this though, you will probably need a special T9 torx screwdriver. Or, you can try to simply pry the thing apart, but please, as before, use proper safety measures.
On top of making sure you completely sure your information is gone, this can work out to be a good stress reliever.
Now you have the tools to make sure your identity is safe if you want to get rid of an old hard drive. Know of any other tools or methods? Let us know in the comments below.
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I might also suggest a friendly reminder – please emphasize proper disposal of these materials as well.
These are not items to simply be “thrown away.” In fact, if you haven’t actually destroyed the drive, but only safely erased it, many places will happily accept a donation to be reallocated to those that could benefit.
That’s a good point. No need to throw out a properly erased drive that could easily be used by someone else. As always, always dispose of things properly!
Great article Mike! It’s articles like this that keep me coming back to MUO!
For you “old-timers” who don’t believe that the format command zeros out the harddrive, here is a reference that explains the change in the format command for Microsoft Windows: http://support.microsoft.com/k…
Another good way to erase a harddrive is to use a utility from CMRR that uses an ATA command to cause the drive to erase itself. This method is not only fast, but causes the drive to erase the spare sectors that have been taken out of service due to checksum (disk surface) failures. More info here: http://cmrr.ucsd.edu/people/Hu…
If you want to get physical, take the platters out and give them a good sanding with some all purpose sandpaper.
Great article Mike! It’s articles like this that keep me coming back to MUO!
For you “old-timers” who don’t believe that the format command zeros out the harddrive, here is a reference that explains the change in the format command for Microsoft Windows: http://support.microsoft.com/kb/941961
Another good way to erase a harddrive is to use a utility from CMRR that uses an ATA command to cause the drive to erase itself. This method is not only fast, but causes the drive to erase the spare sectors that have been taken out of service due to checksum (disk surface) failures. More info here: http://cmrr.ucsd.edu/people/Hughes/SecureErase.shtml
If you want to get physical, take the platters out and give them a good sanding with some all purpose sandpaper.
I was actually gonna include SecureErace in this article, but wasn’t able to get it to work properly. Maybe some of you all will have better luck.
You could also turn an old hard drive into a new external hard drive with the right hardware.
Yep, if you get an external enclosure, you could easily use an old drive for external storage.
The physical method is probably also the least secure. There are companies that make a very good living recovering data on hard drives that have been through fires, floods, run over by a truck, whatever. The hammer might be a good follow-up to proper erasing by software.
If you were to completely destroy the disk thoroughly, physical destruction can be just as secure as another type of erase.
Like formatting and other methods, its all about how thoroughly you perform the action.
I once found a computer on the side of the road. Pretty old one, but it had a 40GB hard drive. I plugged it into one of my old computers and went through the data.
Turns out to be from a realestate agent. Still had all their emails, and a few documents with people’s contact details on them.
Suppose organisations should take better care of what they do with old hardware. Although the powerbox doesn’t work, doesn’t mean the harddrive doesn’t.
In the physical destruction category; A drill press with a 3/4 inch bit works well. Just be sure it goes completely through the drive to include the platters. And, as stated above, always wear the proper safety equipment.
Recovering data from a “drilled” drive may be possible, but very expensive. Organizations like the CIA or NSA can probably recover such data. BUT, if the CIA or NSA are going to that extreme, you have other, more pressing problems than just disposing of a hard drive.
Good Tip!
I second Paul’s comment. Here’s a short video from my employer about drilling hard drives: http://www.youtube.com/watch?v…
I’ve tested these secure “Eraser” programs that work within the OS, and I have tested numerous recovery programs. I am always able to recover some of the data with one program or another after it was supposedly securely erased.
Darik’s Boot and Nuke is the only program that I trust. I have used it and have never been able to recover anything.
Thanks for the information. I myself found DBAN to be quite thorough.
I second Paul’s comment. Here’s a short video from my employer about drilling hard drives: http://www.youtube.com/watch?v=J8mJtEjKxLM
You may also use Truecrypt and simply choose the “Encrypt system Partition/Drive” option on that specific hard drive. I guess this will have the same effect on data previously stored on the drive… It will be fully erased! Check http://truecrypt.org
You may also use Truecrypt and simply choose the “Encrypt system Partition/Drive” option on that specific hard drive. I guess this will have the same effect on data previously stored on the drive… It will be fully erased! Check http://truecrypt.org
Thanks for the heads up. Encryption, though pretty thorough, would not be as complete as a quick run of DBAN though.
The University of Southern California San Diego developed a drive wiping program for the National Institute of Standards and Technology that erases hard drives including their alternate tracks It can be found at http://cmrr.ucsd.edu/people/Hu… and is FREE
The University of Southern California San Diego developed a drive wiping program for the National Institute of Standards and Technology that erases hard drives including their alternate tracks It can be found at http://cmrr.ucsd.edu/people/Hughes/SecureErase.shtml and is FREE
Even after a DOD method format data is alway recoverable. You can also recover after a magnet swipe. I you are scaried your data is not safe do not trow the drive away, this also goes for USB drive
True safety is never letting it fall into the wrong hands to begin with. Good point!
This will not work, tried it… This will fool certain recovery programs though.
Sorry, Clicked the wrong “Reply to this comment”
What about formatting the disk with different file system, such as ext4 of Linux?
You can also fill the the disk with random files after 1st format then reformat again.
That could work, but leaves some security questions up in the air. Like I said before, if you want to make sure, nothing beats a DBAN run and physical destruction.
This will not work, have tried it… This will fool certain recovery programs though.
I have a request, please write an article how to completely erase off handycam’s hard drive. Many people need to know this before selling off their handycams or giving it to some friend temporarily. How can we completely erase handycam’s hard drive so that others cannot recover old video files anymore?